This invention relates to an improved jack for a horizontally extending trailer tongue.
The front end of a trailer is generally supported by a trailer tongue jack when the trailer is parked, that is, not connected to a towing vehicle. The typical trailer tongue jack is secured to a horizontally extending trailer tongue and has a base plate at the lower end of the jack. The jack is usually in the form of an elongated shaft. The shaft typically has an upper portion that is secured to the trailer tongue and a lower portion that is telescopic with respect to the shaft. An upper crank arm that can be rotated about a vertical axis or, in some cases, about a horizontal axis, is utilized to telescopically extend or retract the lower portion of the elongated shaft. As the lower portion of the shaft is telescopically extended or withdrawn with respect to the upper portion, the elevation of the trailer tongue can be varied.
When a vehicle is backed up to engage a trailer hitch that is secured to the forward end of a trailer tongue, precise maneuvering is required. A vehicle may be required to back up several times for alignment with the trailer hitch secured to the trailer tongue.
For these reasons a need exists to provide an improved system by which a trailer tongue may be moved so that a trailer hitch on the trailer tongue may be positioned to engage a ball hitch on the rear end of a vehicle.
Others have addressed this problem as revealed in the following previously issued patents:
A problem exists with trailer tongue jacks as illustrated and described in the above-referenced U.S. Patents. Specifically, there does not exist, to the knowledge of the applicant, a trailer tongue jack that is pivotally affixed to a trailer tongue so that it can be pivoted in a first position in which it is horizontal and substantially parallel to a trailer tongue and pivoted to a second position in which it is vertical, that is substantially perpendicular to a trailer tongue, with a wheel at the lower end thereof and a simple lightweight and effective mechanism by which power can be applied manually to move the wheel and the wheel guided so that the trailer tongue can be easily moved to alignment with a ball hitch on a vehicle.
Accordingly, an object of this invention is to provide an improved jack for a trailer tongue having a system of drive gears to achieve a mechanical advantage by which a trailer tongue can be more easily positioned using manual power.
This invention provides an improved jack for a horizontally extending trailer tongue of the type having, at the forward end of the trailer tongue, a trailer hitch that is typically of the type that is attachable and detachable from a ball post affixed to a vehicle.
The improved jack includes a bracket that is attached to a trailer tongue. A longitudinal shaft is supported to the bracket and pivotal between a first position in which the shaft is substantially horizontal and parallel to the trailer tongue and a second position to which the shaft is vertical, that is, at least substantially perpendicular to the trailer tongue. It is in the second position that the trailer tongue jack is used when the trailer is at rest, and also when the trailer tongue jack is used to align the trailer for connection of the trailer hitch to a ball post mounted at the rearward end of a vehicle.
The longitudinal shaft is typically formed of an upper portion and a telescopic lower portion. By means of a first crank arm at the upper end of the longitudinal shaft, the lower portion may be extended or withdrawn telescopically with respect to the upper portion, to thereby, when the shaft is in the vertical position, raise or lower the elevation of the trailer tongue. The lower portion of the elongated shaft is rotatable with respect to the shaft upper portion or, as an alternative arrangement, the shaft upper portion may be rotatably supported to the bracket so that by either means the lower portion of the shaft may be rotated about the shaft longitudinal axis.
Affixed to the lower end of the shaft is a wheel housing. Received by the wheel housing is a wheel that is rotated with respect to the housing about a horizontal axis. A crank arm is rotatably affixed to the wheel housing and has a drive gear that is rotated by the crank arm. A driven gear is affixed to the wheel. An intermediate gear is also supported by the wheel housing. The drive gear is interconnected with the intermediate gear that is, in turn, connected to the driven gear so that when the drive gear is rotated as the crank arm is rotated, the intermediate gear and the driven gear and thereby the wheel is rotated. In one embodiment, a first flexible chain, which typically may be such as a bicycle chain, interlinks the drive gear and the intermediate gear and a second flexible chain interlinks the intermediate gear and the driven gear. Instead of the chain, belts could be employed. In another embodiment, the drive gear is directly coupled to an intermediate gear that is then rotationally coupled to the driven gear. This can be accomplished by teeth on the drive gear directly meshing with teeth on the intermediate gear which is coupled to rotate the driven gear. The intermediate gear is employed so that a direct gear drive with improved mechanical advantage extends between the drive gear and the driven gear. Irrespective of the particular system used for coupling the rotation of the crank arm to turning the wheel, it is important that a mechanical advantage be obtained so that a relatively small force is required to rotate the crank arm to move the wheel and thereby move the trailer tongue when aligning a trailer hitch to a ball post.
In the process of aligning a trailer hitch with a ball post it is nearly always necessary to change the direction of movement of the trailer tongue. Direction change is accomplished by rotating the lower portion of the elongated shaft about its longitudinal axis to thereby change the direction of travel of the wheel. The lower portion of the elongated shaft can be rotated by use of the crank arm or, in another embodiment, a guide handle may be extended from the lower portion of the shaft or, more specifically, from the wheel housing. The handle may have a hinged portion so that it can be pivoted out of the way except when being used to guide the direction of travel of the wheel.
For convenience of use, it is important that the drive gear be rotated about an axis that is elevated well above the axis of the wheel so that an operator does not have to bend over excessively to rotate the crank arm to achieve rotation of the drive gear. In the invention herein, the axis of rotation of the crank arm is positioned well above the lower end of the longitudinal shaft having the wheel housing affixed to it.